81925579 has 2 divisors, whose sum is σ = 81925580. Its totient is φ = 81925578.

The previous prime is 81925577. The next prime is 81925619. The reversal of 81925579 is 97552918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81925579 - 2¹ = 81925577 is a prime.

Together with 81925577, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81925577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40962789 + 40962790.

It is an arithmetic number, because the mean of its divisors is an integer number (40962790).

Almost surely, 2^81925579 is an apocalyptic number.

81925579 is a deficient number, since it is larger than the sum of its proper divisors (1).

81925579 is an equidigital number, since it uses as much as digits as its factorization.

81925579 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 46.

The square root of 81925579 is about 9051.2749930604. The cubic root of 81925579 is about 434.3166776344.

The spelling of 81925579 in words is "eighty-one million, nine hundred twenty-five thousand, five hundred seventy-nine".